Finally, I've been able to lay my hands on two books: VERTIGO The Making of an Alfred Hitchcock Classic and The Making of PSYCHO. All choked up with that new info, I have re-worked the opinions I present here. Not so many changes were in order, after all.

The first Hitchcock movie I saw was To Catch A Thief. How disappointing - everybody had been raving about how good this guy Hitchcock was - but I had seen many much better films. It opens with a sequence where a cat walks on a tile roof, which made the audience laugh. Still can't see what's so funny about that.
To me, Hitchcock was stark staring mad. He not only carried on like he was a maniac, he really was one. He was also much too fat. Not a sympathetic character at all. I'll quote you some out of Alexander Walker's book on la Hepburn maggiore, Audrey - her real story:

All Hitchcock had told [Hepburn] of the role was that she would play a courtroom lawyer [...] who defends her father when he is accused of murder. [...] Hitchcock had assured her, in the tone he used when wheedling actresses into doing what he wanted, that she would make 'a very pretty Portia' [...] What he neglected to tell her was that the plot would require her to be sexually assaulted. The pleasures that come from assaulting well-bred ladies in motion pictures were not then as well recognized a Hitchcock trademark as [later]. (page 166/7)
Audrey took her first comprehensive look at the complete script of the Hitchcock film. In her present state, having just lost a child, she reacted with disbelieving horror. Her character was going to be raped in a London park. (page 169)
She could not - and resolved she would not - play this part. But she had signed a contract with Hitchcock. [...] There was only one way out of the dilemma - and it did not require the threat of litigation to make Audrey embrace it. She became pregnant again. [...] With bad grace he tore up the agreement - and forever held it against her, considering it a deliberately engineered breach of contract.

Then, Hitchcock has made the most terrible trash. Sure, everybody has ups and downs, but a very minor Kurosawa movie is a very good film. Some of what Hitchcock made is really not worth looking at in almost every sense. It's often heard that you shouldn't judge somebody by their bad products, but that's a show biz dictum I can't agree with.To Catch a Thief was followed up with The Trouble with Harry,
The Man Who Knew too Much and The Wrong Man ; not bad movies, but especially the last one practically forgotten. It was a great surprise to have the next one turn out to be not only the most beautiful movie Hitchcock ever made, but a real masterpiece:

There are so many fine visuals in this movie that it made me jump to the conclusion that, somehow, Saul Bass had his hand in it. Well, I was wrong, as Stefan Blau assures me - and he ought to know. Examples: There is a most weird shot, when James Stewart for the second time kisses Kim Novak for the first time. The camera dollies around the couple in a hotel room, and on behind them we see the setting of their first first kiss. It may have been done with a revolving plateau for the actors and rear projection or a moving matte/bluescreen. And the music!
I had my suspicions about several other details. The light that keeps diminishing in the bookshop. The wave crashing behind an embrace. A cloud of pigeons coming by at exactly the right moment. All of these, I graciously and even happily concede, could very well have been thought of by Hitch. There are just so many of them.The nightmare has been done by John Ferren.

After this remarkable trio, Hitchcock went on to makeThe Birds, which at least had a very good script by Evan Hunter;Marnie, a boring piece of Freudian nonsense,Torn Curtain, a spy drama nobody wants to remember,Family Plot, which I thought much better again,
and, in London, Frenzy which was really bad -a good illustration of how a director's name ultimately depends on the film crews working for him.